The present disclosure relates to a multilayer electronic component, and more specifically, to a compact multilayer electronic component having excellent magnetic properties, capable of being mass-produced.
Among electronic components, an inductor, an important passive element constituting an electronic circuit together with a resistor and a capacitor, is used to remove noise or to constitute an LC resonance circuit. Various types of inductor exist, such as a multilayer type inductor, a wire-wound type inductor, a thin film type inductor, or the like, according to a structure thereof.
Recent electronic devices are required to be relatively small in terms of size. However, in general DC-DC converters, due to an increase in components such as inductors, condensers, and the like, an area of power circuit may be increased.
Therefore, in order to achieve miniaturization of electronic devices, first, components are required to be relatively small. In the case in which a switching frequency of a DC-DC converter is high, the number of inductors or condensers required may be reduced, and miniaturization of the components may be facilitated. Recently, in accordance with the implementation of highly functional integrated Circuits (IC), according to advances in semiconductor manufacturing technology, efforts to increase the magnitude of switching frequencies have been undertaken.
As part of this trend, a wire-wound type inductor having lead wires wound around metal-based magnetic materials has largely been used as a power inductor in a DC-DC converter circuit according to the related art. However, the inductor has a fundamental limitation in miniaturization. Therefore, in recent years, multilayer inductors have increasingly been used in the place of wire-wound type inductors.
Meanwhile, multilayer inductors have disadvantages in that changes in inductance values according to the application of currents may be relatively large, as compared to the wire-wound type power inductors.
In multilayer inductors, magnetic layers and conductor patterns are alternately stacked, the conductor patterns being electrically connected between the magnetic layers, thereby forming coil conductors. Since ferrite-based oxides, mainly used as magnetic materials of multilayer inductors have high degrees of permeability and electrical resistance, but relatively low magnetic saturation density, there are disadvantages in that deteriorations in inductance due to magnetic saturation may be relatively large and DC bias characteristics may be poor.
That is, when DC power is applied to a multilayer inductor having the above-described configuration, magnetic saturation is generated in a magnetic body due to an increase in current, such that inductance properties may be rapidly deteriorated.
Due to the above-described reason, in the case of a multilayer power inductor using ferrite as a magnetic material according to the related art, there is a problem in that a separate non-magnetic layer should be interposed between layers to form a separation distance therebetween in order to secure DC bias characteristics.
In addition, in inductors using ferrite, circuits should be installed on a ferrite plate and a sintering process should subsequently be performed thereon. Due to a distortion phenomenon occurring during the sintering process, there is a limitation in securing a predetermined amount or more of inductance or DC bias characteristics, whereby it is difficult to increase an area of the ferrite plate. In particular, in accordance with the recent trend for inductors to be miniaturized and products having a thickness of 1 mm or less to be manufactured, the area is inevitably further limited. Therefore, it is difficult to provide various forms of inductance and DC bias characteristics.
In order to solve this problem, a magnetic metal material having a high magnetic saturation value, instead of using a ferrite magnetic material having a low magnetic saturation value, has been applied to multilayer electronic components. However, in a process of manufacturing a multilayer electronic component, a high-temperature sintering process is required in order to sinter conductor patterns formed in a magnetic body, unlike a process of manufacturing a thin film inductor. Such a high-temperature sintering process may cause the metal magnetic material to be rapidly oxidized and lose magnetic properties, and thus, the magnetic body using the metal magnetic material could not be applied to the multilayer electronic component according to the related art.
Japanese Patent Laid-Open Publication No. JP 2007-027354 discloses a method of manufacturing a magnetic material in a multilayer electronic component, in which magnetic layers formed of magnetic paste containing a glass component in addition to alloys and conductor patterns are stacked and sintered under nitrogen atmosphere at a high temperature, and then the sintered product is impregnated with a thermosetting resin.
However, since the description of Japanese Patent Laid-Open Publication No. JP 2007-027354 includes a composite of metals and resin in order to secure insulation properties, sufficient permeability may not be obtained, and in order to maintain the resin therein, a relatively low-temperature heat treatment should be performed thereon, such that internal electrodes are not densified.